Bugfix/pg connections (#2002)

* increase max_connections to 150 in all docker files

* lower celery worker concurrency to 6

deployment/docker_compose/docker-compose.gpu-dev.yml

@@ -300,6 +300,7 @@ services:
 
   relational_db:
     image: postgres:15.2-alpine
+    command: -c 'max_connections=150'
     restart: always
     environment:
       - POSTGRES_USER=${POSTGRES_USER:-postgres}